Image correction information recording device

ABSTRACT

An image correction information recording device comprises a memory card having an image recording area, in which an image signal is recorded, and an information recording area, in which information relating to the image signal recorded in the image recording area is recorded. The image signal is subjected to a plurality of image correction processes in a processing order, and recorded in the memory card. The information recording area has an image process order recording area, in which data indicating the process order is recorded. When the image signal is read from the memory card, the image signal is subjected to restoration processes, the contents of which are the opposite of the image correction processes, in a restoring order which is the reverse of the processing order.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic still camera in which animage signal, obtained by an imaging device, for example, is subjectedto an image correction process and recorded in a recording medium.

2. Description of the Related Art

A conventional electronic still camera is constructed in such a mannerthat an image signal obtained by an imaging device is subjected to imagecorrection processes, including a white balance process, a gammacorrection and so on, and then recorded in a recording medium. The imagecorrection processes conform to the indication characteristics of adisplay device on which an image obtained by the electronic still camerais indicated, so that a color image, being as close as possible to theoriginal image, can be reproduced, due to the image correctionprocesses.

Conventionally, the display device cannot be changed. However, if thedisplay device is changed to another display device, and the imagesignal, recorded in the recording medium, is reproduced to be indicatedon the other display device, the image indicated by the other displaydevice may not have a satisfactory quality, since the image signal hasnot been subjected to image correction processes conforming to the otherdisplay device.

SUMMARY OF THE INVENTION

Therefore, an object of the invention is to provide an image correctiondevice by which an image signal can be subjected to optimum imagecorrection processes when using an arbitrary display device.

According to the present invention, there is provided an imagecorrection information recording device provided in an electronic stillcamera, comprising an image correcting processor, an image signalrecording processor and a processing order recording processor. Theimage correcting processor performs a plurality of image correctionprocesses to an image signal in a processing order to generate acorrected image signal. The image signal recording processor records thecorrected image signal in a recording medium. The processing orderrecording processor records the processing order in the recordingmedium.

Further, according to the present invention, there is provided an imagerecording medium comprising an image recording area and an informationrecording area. An image signal can be recorded in the image recordingarea. The image signal is subjected to a plurality of image correctionprocesses in a processing order, which is also recorded in theinformation recording area.

Furthermore, an image signal processing device processes a correctedimage signal, which has been obtained by performing a plurality of imagecorrection processes to an image signal in a processing order. Thedevice comprises a processing order determining processor and an imagesignal restoring processor.

The processing order determining processor determines the processingorder. The image signal restoring processor performs restorationprocesses, the contents of which are the opposite of the imagecorrection processes, to the corrected image signal in a restoringorder, which is the reverse of the processing order.

Further, according to the present invention, there is provided an imagesignal processing system comprising an image correcting processor, animage signal recording processor, a processing order recordingprocessor, a processing order reading processor, and an image signalrestoring processor. The image correcting processor performs a pluralityof image correction processes to an image signal in a processing orderto generate a corrected image signal. The image signal recordingprocessor records the corrected image signal in a recording medium. Theprocessing order recording processor records the processing order in therecording medium. The processing order reading processor reads theprocessing order from the recording medium. The image signal restoringprocessor performs restoration processes, the contents of which are theopposite of the image correction processes, to the corrected imagesignal in a restoring order which is the reverse of the processingorder.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from the description ofthe preferred embodiments of the invention set forth below, togetherwith the accompanying drawings, in which:

FIG. 1 is a block diagram of an electronic still camera having an imagecorrection information recording device of an embodiment of the presentinvention;

FIG. 2 is a view showing an example of the allocation of data areas ofan image file formed in a memory card;

FIG. 3 is a block diagram of an image reproduction device of theembodiment of the present invention; and

FIGS. 4A and 4B show a flow chart of a program by which an image signalis read from the memory card and indicated on a crystal display device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described below with reference toembodiments shown in the drawings.

FIG. 1 shows a block diagram of an electronic still camera having animage correction information recording device of an embodiment of thepresent invention.

A system controller 11 has a microcomputer, by which the imagecorrection information device is controlled as a whole. An imagingdevice (charge coupled device (CCD)) 12 is disposed on an optical axis(not shown), so that an image is formed on a light receiving surface ofthe CCD 12. The CCD 12 is provided with a color filter on the lightreceiving surface. The color filter having a red (R) filter element, agreen (G) filter element and a blue (B) filter element, which aredisposed in a predetermined arrangement, according to the Beyar method,for example. Pixel signals corresponding to the image formed on the CCD12 are outputted from the CCD 12. Then, the pixel signals are subjectedto a predetermined process, such as correlated double sampling (CDS), ina CDS circuit 13, and are converted into digital signals by an A/Dconverter 14. The digital pixel signals are separated into R, G and Bpixel signals in a color separation (CS) circuit 15.

A color temperature sensor 16 is connected to the system control circuit11, so that information indicating the color temperature of the ambientlight of a subject to be photographed is inputted thereto. The R, G andB pixel signals are subjected to a white balance adjustment inaccordance with the color temperature information in a white balance(WB) adjustment circuit 21. The pixel signals outputted from the whitebalance adjustment circuit 21 are subjected to a shading correction in ashading correction (SC) circuit 22. The pixel signals subjected to theshading correction are then inputted to a defect correction (DC) circuit23, in which a defect correction is performed, so that a pixel signalcorresponding to a photo-diode, which has a defect, existing in the CCD12 is generated.

The pixel signals, to which the defect correction has been performed,are subjected to a gamma correction in a gamma correction (GC) circuit24. The output signals of the gamma (γ) correction 24 are inputted intoa matrix calculation (MC) circuit 25, in which a matrix calculation iscarried out, so that the R, G and B pixel signals are converted into aluminance signal and a color difference signal. The luminance signal andthe color difference signal are then inputted into aknee-process/color-depression (KC) circuit 26, in which the luminancesignal is subjected to a knee process and the color difference signal issubjected to a color depression process. The output signals of theknee-process/color-difference circuit 26 are subjected to a peripheralcorrection in a peripheral correction (PC) circuit 27, so that an edgeof the image is emphasized, for example.

The output signals of the peripheral correction circuit 27 aretemporarily stored in a memory 31. The luminance signal and the colordifference signal are read from the memory 31, and may be subjected toan image compression process, according to the JPEG algorithm, forexample, in a compression/expansion circuit 32 to generate a compressedimage signal. The compressed image signal is then temporarily stored inthe memory 31, before being read to a memory card controller 33.Alternately, the image signal is read directly from the memory 31 to thememory card controller 33. The format of the compressed image signal orthe image signal is converted to a predetermined format in the memorycard controller 33, and thus the compressed image signal or image signalis recorded in a memory card (recording medium) M. The compressed imagesignal or image signal recorded in the memory card M, is read therefrom,and the format of the compressed image signal or image signal isconverted to a predetermined format in the memory card controller 33,before being temporarily stored in the memory 31. The compressed imagesignal is subjected to an image expansion process, according to the JPEGalgorithm, for example, and is re-stored in the memory 31.

The luminance signals and the color difference signals, which are readfrom the memory 31 or are outputted from the peripheral correctioncircuit 27, are converted to a video signal, according to the NTSCsystem in an encoder 34, which is then converted into an analog videosignal by a D/A converter 35. Then, the analog video signal is inputtedto a display device 36, having a liquid crystal display (LCD), so thatan image is indicated on a surface of the liquid crystal display.

FIG. 2 is a view showing an example of the allocation of data areas ofan image file formed in the memory card M (see FIG. 1). The image fileis composed of an image recording area M1, in which an image signal isrecorded, and an information recording area M2, in which informationrelating to the image recording area M1 is recorded. A compressed imagesignal, obtained from an image compression process of thecompression/expansion circuit 32, or an image signal is recorded in theimage recording area M1. The information recording area M2 has a headerarea M3 and an image processing order recording area M4. Information,generated when the compressed image signal or image signal is recordedin the image recording area M1, is stored in the header area M3. Dataindicating a processing order, in which an image signal recorded in theimage recording area M1 is processed in the white balance adjustingcircuit 21, the shading correction circuit 22 and so on, are recorded inthe image processing order recording area M4.

In the circuits shown in FIG. 1, the white balance adjustment, theshading correction, the defect correction, the gamma correction, thematrix calculation, the knee-process/color-depression and the peripheralcorrection are performed in this order. Accordingly, in the imageprocessing order recording area M4 contained in the informationrecording area M2, data indicating the processing order are recorded bythe system control circuit 11, via the memory card controller 33.

“PROCESS START” indicates a starting address of the image processingorder recording area M4. “1. W(R/G=0.7, B/G=1.4)” implies that the whitebalance adjustment has been carried out first, in which a rednormalization coefficient R/G is 0.7, and a blue normalizationcoefficient B/G is 1.4. “2. S(±50%)” implies that the shading correctionhas been carried out second, in which the maximum correction amount is50%. “3. D (×=654, Y=321)” implies that the defect correction has beencarried out third, in which the coordinates or the position of thedefect pixel is (654, 321). “4. G(0.45)” implies that the gammacorrection has been carried out fourth, in which the gamma correctionamount is 0.45. “5. M(RGB→YC)” implies that the matrix calculation hasbeen carried out fifth, in which R, G and B pixel signals have beenconverted to a luminance signal and color difference signals. “6.N(0.25)” implies that the knee process has been carried out sixth, inwhich the compression amount is 25%. “7. A(H=0.1, V=0.1)” implies thatthe peripheral correction has been carried out seventh, in which thecorrection is performed in such a manner that the luminance differencein a periphery is emphasized by 10% in horizontal and verticaldirections, respectively. “PROCESS END” implies the end address of theimage processing order recording area M4.

FIG. 3 shows a block diagram of an image reproduction device of theembodiment of the present invention. A system controller 41 has amicrocomputer, by which the image reproduction device is controlled as awhole. Data indicating the processing order, in which the imagecorrection processes are performed to the image signal, are recorded inthe memory card M, in addition to the image signal, as shown in FIG. 2.

The memory card M is attached to a memory card controller 42. The formatof the image signal, read from the memory card M, is converted to apredetermined format by the memory card controller 42, and then theimage signal is stored in a buffer memory 43. The image signal is readfrom the buffer memory 43, and is then subjected to an image expansionprocess, if required, according to the JPEG algorithm, for example, in acompression/expansion circuit 44, so that an image signal, which hasbeen compressed, is expanded to generate a non-compressed image signal,which is then stored in the buffer memory 43.

The image signal stored in the buffer memory 43 is read therefrom, andis stored in an indication memory 45. Then, the image signal is readfrom the indication memory 45, and is subjected to restorationprocesses, the contents of which are opposite to the contents of theimage correction processes, which were performed prior to the imagesignal being recorded in the memory card M, in a restoring order whichis the reverse of the processing order. Thus, the image signal, havingbeen subjected to the restoration processes, is subjected to furthersequence of predetermined image correction processes corresponding tothe indication characteristics of the liquid crystal display (LCD) 47,and then, the format of the image signal is converted to a predeterminedformat by an LCD controller 46. The image signal is outputted to the LCD47, whereby an image corresponding to the image signal is indicated onthe LCD 47.

An operation switch 48, by which an image signal is read from the memorycard M and a process, which includes an image process, is performed, isconnected to the system control circuit 41.

FIGS. 4A and 4B show a flow chart of a program by which the image signalis read from the memory card M and the image is indicated on the LCD 47.The program is executed by operating the operation switch 48.

In Step 101, an image file, which is designated by the operation switch48, is accessed, so that the image processing order, recorded in theimage processing order recording area M4, corresponding to the imagefile is read therefrom. In Step 102, the image signal recorded in theimage recording area M1 of the image file is read therefrom, andtransmitted to the buffer memory 43. In Step 103, based on theinformation recorded in the image recording area M1, it is determinedwhether the image signal has been subjected to an image compressionprocess. When the image signal has been compressed, Step 104 is executedin which an image expansion process is performed on the compressed imagesignal, and when the image signal has not been subjected to the imagecompression process, Step 104 is skipped.

In Step 105, the obtained image signal is stored in the indicationmemory 45, and an image corresponding to the image signal is indicatedon the LCD 47. In Step 106, the image processing order, read in Step101, is superimposed on the image and thus also indicated on the LCD 47.

In Steps 107 through 109, the restoration processes, the contents ofwhich being opposite to the image correction processes, are executed,based on an operation of the operation switch 48.

It is determined in Step 107 whether the restoration processes are to beperformed. When the restoration processes are to be performed, theroutine goes to Step 108, in which a command signal, indicating whichstage the process should be returned to, is inputted in accordance withthe operation of the operation switch 48. In Step 109, the restorationprocesses are carried out from the last image process to the imageprocess designated by the operation switch 48, in the restorationprocessing order, in accordance with the processing order read from thememory card M. For example, regarding the image file shown in FIG. 2,when the process should be returned to the gamma process stage, thereverse of the peripheral correction, the reverse of the knee process,the reverse of the matrix calculation, and the reverse of the gammacorrection are carried out in this order. The results of thecalculations obtained from the execution of the reversed processes arestored in the buffer memory 43.

Then, the routine returns to Step 105, in which the image signal forindicating an image on the LCD 47 is stored in the indication memory 45,so that the image is indicated on the LCD 47. Then, in Step 106, theimage processing order, read in Step 101, is superimposed on the image,so as to also be indicated on the LCD 47.

Step 107 is again executed, and when further restoration processes areto be performed, Steps 108 and 109 are re-executed. Conversely, whenfurther restoration processes are unnecessary, the routine goes to Step111.

In Step 111, it is determined, based on the operation of the operationswitch 48, whether additional image correction processes are to beperformed. For example, when the restoration processes have beenperformed as far as the gamma correction, as described above, andanother gamma correction is required, the desired image correctionprocess (i.e. the other gamma correction) is performed in Step 112, andthe resulting image signal, obtained by the other gamma correction, isstored in the buffer memory 43. Then, the routine returns to Step 105,so that the operations described previously are executed again.

Conversely, when it is determined in Step 111 that additional imagecorrection processes are unnecessary, Step 113 is executed in which itis determined whether the image signal, which is stored in the buffermemory 43 at present, i.e. stored in the buffer memory 43 in Step 109 or112 when the restoration or correction processes were performed, is tobe recorded in the memory card M. When the image signal is to berecorded in the memory card M, Step 114 is executed in which it isdecided whether the image signal should be compressed and the resultingimage signal is recorded in the memory card M. At this time, the newprocessing order (i.e. the altered processing order) is recorded in theimage processing order recording area M4 of the memory card M, and thusthe record of the processing order is renewed. If the image signal andthe processing order need not be recorded in the memory card M, Step 114is skipped, and this program ends.

As described above, in the embodiment, since the processing order of theimage correction processes, which is performed on recording an imagesignal in the memory card M, is recorded in the memory card M, theopposite of the image correction processes can be performed. Therefore,when the image signal is read from the memory card M, to reproduce andindicate the image on an arbitrary display device, the image correctionprocesses conforming to the indication characteristics of the displaydevice can be performed, so that the image, indicated by the displaydevice, has a high quality.

Note that the contents of the image correction processes, contained inthe parentheses in FIG. 2, are not necessarily recorded in the memorycard M. Namely, by recording only the processing order of the imagecorrection processes in the memory card M, the image signal can berestored, with a relatively high accuracy, to a state equivalent to thatprior to subjecting the image signal to the image correction processes,and therefore, an effect similar to that of the above describedembodiment can be obtained.

Although the embodiments of the present invention have been describedherein with reference to the accompanying drawings, obviously manymodifications and changes may be made by those skilled in this artwithout departing from the scope of the invention.

The present disclosure relates to subject matter contained in JapanesePatent Application No. 9-106705 (filed on Apr. 9, 1997) which isexpressly incorporated herein, by reference, in its entirety.

What is claimed is:
 1. An image correction information recording deviceprovided in an electronic still camera, comprising: an image correctingprocessor that performs a plurality of image correction processes to animage signal in a processing order to generate a corrected image signal;an image signal recording processor that records said corrected imagesignal to a recording medium; and a process order recording processorthat records data, indicating said processing order in which said imagecorrection processes were performed, to said recording medium.
 2. Animage correction information recording device according to claim 1,wherein said plurality of image correction processes includes a gammacorrection.
 3. An image correction information recording deviceaccording to claim 1, wherein said plurality of image correctionprocesses includes at least one of a white balance adjustment, a shadingcorrection, a defect correction, a matrix calculation, a knee process, acolor depression process and a peripheral correction.
 4. An imagecorrection information recording device according to claim 1, whereinthe contents of said plurality of image correction processes arerecorded in said recording medium.
 5. An image correction informationrecording device according to claim 1, wherein said recording medium hasan image recording area, in which said corrected image signal isrecorded, and an information recording area, in which data indicatingsaid processing order is recorded, said information recording areacontaining said data corresponding to said image recording areacontaining said corrected image signal.